Positioning structure, backlight source, display module and display device

The present disclosure provide a positioning structure, a backlight source, a display module, and a display device, and the positioning structure is applied to a backlight source include a light guide plate and an optical film, the positioning structure includes a structural body, the structural body includes: multiple protruding structures spaced from each other, an end portion of each of the protruding structures adjacent to the light guide plate forming a contact positioning surface, and at least two contact positioning surfaces located in a same plane forming a first positioning surface for positioning an end surface of the light guide plate; wherein the structural body is provided with a second positioning surface for positioning an end surface of the optical film of the backlight source, and the second positioning surface and the first positioning surface are located at different planes.